package baidu

import (
	"bytes"
	"context"
	"encoding/json"
	"fmt"
	"io"
	"net/http"
	"net/http/httptest"
	"os"
	"path"
	"reflect"
	"strconv"
	"strings"
	"sync"
	"testing"
	"time"

	"gitea.dddbg.com/youbin/bdrclone/internal/config"
)

func TestRemotePathWithRoot(t *testing.T) {
	client := New(testConfig("token"))
	for input, want := range map[string]string{
		"/": "/apps/bdrclone", "docs/a.txt": "/apps/bdrclone/docs/a.txt", "/../a": "/apps/bdrclone/a",
	} {
		if got := client.RemotePath(input); got != want {
			t.Errorf("RemotePath(%q) = %q, want %q", input, got, want)
		}
	}
	if got := client.APIPath("/apps/bdrclone/docs/a.txt"); got != "/docs/a.txt" {
		t.Fatalf("APIPath = %q", got)
	}
}

func TestExpiredTokenRefreshesAndPersists(t *testing.T) {
	var saved Token
	var listCalls int
	server := httptest.NewServer(http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
		switch r.URL.Path {
		case "/oauth/2.0/token":
			if r.URL.Query().Get("refresh_token") != "refresh-old" {
				t.Errorf("unexpected refresh token: %q", r.URL.Query().Get("refresh_token"))
			}
			fmt.Fprint(w, `{"access_token":"access-new","refresh_token":"refresh-new","expires_in":3600}`)
		case "/rest/2.0/xpan/file":
			listCalls++
			if r.URL.Query().Get("access_token") != "access-new" {
				t.Errorf("unexpected access token: %q", r.URL.Query().Get("access_token"))
			}
			if got := r.Header.Get("User-Agent"); got != "pan.baidu.com" {
				t.Errorf("User-Agent = %q", got)
			}
			fmt.Fprint(w, `{"errno":0,"list":[]}`)
		default:
			http.NotFound(w, r)
		}
	}))
	defer server.Close()
	cfg := testConfig("expired")
	cfg.RefreshToken = "refresh-old"
	cfg.ExpiresAt = time.Now().Add(-time.Hour)
	client := New(cfg, WithEndpoints(server.URL, server.URL, server.URL), WithTokenSaver(func(token Token, _ time.Time) error {
		saved = token
		return nil
	}))
	if _, err := client.List(context.Background(), "/"); err != nil {
		t.Fatal(err)
	}
	if saved.AccessToken != "access-new" || saved.RefreshToken != "refresh-new" {
		t.Fatalf("saved token = %+v", saved)
	}
	if listCalls != 1 {
		t.Fatalf("list calls = %d", listCalls)
	}
}

func TestOpenUsesOfficialUserAgentAndRange(t *testing.T) {
	var server *httptest.Server
	metadataCalls := 0
	server = httptest.NewServer(http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
		switch r.URL.Path {
		case "/rest/2.0/xpan/multimedia":
			metadataCalls++
			fmt.Fprintf(w, `{"errno":0,"list":[{"fs_id":42,"dlink":%q}]}`, server.URL+"/download?x=1")
		case "/download":
			if got := r.Header.Get("User-Agent"); got != "pan.baidu.com" {
				t.Errorf("User-Agent = %q", got)
			}
			if got := r.Header.Get("Range"); got != "bytes=2-5" {
				t.Errorf("Range = %q", got)
			}
			if got := r.URL.Query().Get("access_token"); got != "token" {
				t.Errorf("access_token = %q", got)
			}
			w.WriteHeader(http.StatusPartialContent)
			fmt.Fprint(w, "2345")
		default:
			http.NotFound(w, r)
		}
	}))
	defer server.Close()
	client := New(testConfig("token"), WithEndpoints(server.URL, server.URL, server.URL))
	body, err := client.Open(context.Background(), File{FSID: 42, Path: "/a"}, 2, 4)
	if err != nil {
		t.Fatal(err)
	}
	defer body.Close()
	b, err := io.ReadAll(body)
	if err != nil {
		t.Fatal(err)
	}
	if string(b) != "2345" {
		t.Fatalf("body = %q", b)
	}
	body, err = client.Open(context.Background(), File{FSID: 42, Path: "/a"}, 2, 4)
	if err != nil {
		t.Fatal(err)
	}
	body.Close()
	if metadataCalls != 1 {
		t.Fatalf("download metadata calls = %d, want cached URL to be reused", metadataCalls)
	}
}

func TestUploadMultipartFlow(t *testing.T) {
	content := append(bytes.Repeat([]byte("a"), int(defaultPartSize)), []byte("tail")...)
	file, err := os.CreateTemp(t.TempDir(), "upload-*")
	if err != nil {
		t.Fatal(err)
	}
	if _, err := file.Write(content); err != nil {
		t.Fatal(err)
	}

	var mu sync.Mutex
	parts := map[int][]byte{}
	server := httptest.NewServer(http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
		switch r.URL.Path {
		case "/rest/2.0/xpan/file":
			if err := r.ParseForm(); err != nil {
				t.Error(err)
			}
			switch r.URL.Query().Get("method") {
			case "precreate":
				if r.Form.Get("path") != "/apps/bdrclone/remote.bin" {
					t.Errorf("precreate path = %q", r.Form.Get("path"))
				}
				var blocks []string
				if err := json.Unmarshal([]byte(r.Form.Get("block_list")), &blocks); err != nil || len(blocks) != 2 {
					t.Errorf("block list = %q, err=%v", r.Form.Get("block_list"), err)
				}
				fmt.Fprint(w, `{"errno":0,"return_type":1,"uploadid":"upload-1","block_list":[0,1]}`)
			case "create":
				if r.Form.Get("uploadid") != "upload-1" {
					t.Errorf("create uploadid = %q", r.Form.Get("uploadid"))
				}
				fmt.Fprint(w, `{"errno":0,"fs_id":99,"path":"/apps/bdrclone/remote.bin","server_filename":"remote.bin","size":4194308}`)
			default:
				http.Error(w, "unexpected method", http.StatusBadRequest)
			}
		case "/rest/2.0/pcs/superfile2":
			part, _ := strconv.Atoi(r.URL.Query().Get("partseq"))
			if r.URL.Query().Get("uploadid") != "upload-1" {
				t.Errorf("part uploadid = %q", r.URL.Query().Get("uploadid"))
			}
			if err := r.ParseMultipartForm(defaultPartSize + 1024); err != nil {
				t.Error(err)
				return
			}
			partFile, _, err := r.FormFile("file")
			if err != nil {
				t.Error(err)
				return
			}
			b, err := io.ReadAll(partFile)
			partFile.Close()
			if err != nil {
				t.Error(err)
			}
			mu.Lock()
			parts[part] = b
			mu.Unlock()
			fmt.Fprint(w, `{"md5":"ok"}`)
		default:
			http.NotFound(w, r)
		}
	}))
	defer server.Close()
	cfg := testConfig("token")
	cfg.PartSize = defaultPartSize
	cfg.UploadParts = 2
	client := New(cfg, WithEndpoints(server.URL, server.URL, server.URL))
	entry, err := client.Upload(context.Background(), file, int64(len(content)), "/remote.bin", time.Unix(1_700_000_000, 0), nil)
	if err != nil {
		t.Fatal(err)
	}
	if entry.FSID != 99 {
		t.Fatalf("entry = %+v", entry)
	}
	mu.Lock()
	defer mu.Unlock()
	if !bytes.Equal(parts[0], content[:defaultPartSize]) || !bytes.Equal(parts[1], content[defaultPartSize:]) {
		t.Fatalf("uploaded parts do not match input: sizes %d, %d", len(parts[0]), len(parts[1]))
	}
}

func TestUploadPartRetriesGatewayTimeout(t *testing.T) {
	file, err := os.CreateTemp(t.TempDir(), "retry-upload-*")
	if err != nil {
		t.Fatal(err)
	}
	defer file.Close()
	content := []byte("retry payload")
	if _, err := file.Write(content); err != nil {
		t.Fatal(err)
	}

	attempts := 0
	server := httptest.NewServer(http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
		if r.URL.Path != "/rest/2.0/pcs/superfile2" {
			http.NotFound(w, r)
			return
		}
		attempts++
		_, _ = io.Copy(io.Discard, r.Body)
		if attempts < 4 {
			http.Error(w, "gateway timeout", http.StatusGatewayTimeout)
			return
		}
		fmt.Fprint(w, `{"md5":"ok"}`)
	}))
	defer server.Close()

	client := New(testConfig("token"), WithEndpoints(server.URL, server.URL, server.URL))
	client.uploadRetryDelay = func(int) time.Duration { return 0 }
	if err := client.uploadPartWithRetry(context.Background(), file, "/apps/bdrclone/retry.bin", "upload-1", 0, 0, int64(len(content))); err != nil {
		t.Fatal(err)
	}
	if attempts != 4 {
		t.Fatalf("attempts = %d, want 4", attempts)
	}

	failureAttempts := 0
	failureServer := httptest.NewServer(http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
		failureAttempts++
		_, _ = io.Copy(io.Discard, r.Body)
		http.Error(w, "gateway timeout", http.StatusGatewayTimeout)
	}))
	defer failureServer.Close()
	failureClient := New(testConfig("token"), WithEndpoints(failureServer.URL, failureServer.URL, failureServer.URL))
	failureClient.uploadRetryDelay = func(int) time.Duration { return 0 }
	err = failureClient.uploadPartWithRetry(context.Background(), file, "/apps/bdrclone/retry.bin", "upload-2", 0, 0, int64(len(content)))
	if err == nil || !strings.Contains(err.Error(), "after 6 attempts") {
		t.Fatalf("error = %v", err)
	}
	if failureAttempts != maxUploadAttempts {
		t.Fatalf("attempts = %d, want %d", failureAttempts, maxUploadAttempts)
	}
}

func TestMkdirAllCreatesMissingRemoteDirectories(t *testing.T) {
	directories := map[string]bool{"/apps/bdrclone": true}
	var created []string
	server := httptest.NewServer(http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
		if r.URL.Path != "/rest/2.0/xpan/file" {
			http.NotFound(w, r)
			return
		}
		switch r.URL.Query().Get("method") {
		case "list":
			parent := r.URL.Query().Get("dir")
			entries := make([]File, 0)
			for directory := range directories {
				if directory != parent && path.Dir(directory) == parent {
					entries = append(entries, File{Path: directory, ServerFilename: path.Base(directory), IsDir: 1})
				}
			}
			_ = json.NewEncoder(w).Encode(map[string]any{"errno": 0, "list": entries})
		case "create":
			if err := r.ParseForm(); err != nil {
				t.Error(err)
				return
			}
			directory := r.Form.Get("path")
			if r.Form.Get("isdir") != "1" {
				t.Errorf("isdir = %q", r.Form.Get("isdir"))
			}
			directories[directory] = true
			created = append(created, directory)
			_ = json.NewEncoder(w).Encode(File{Path: directory, ServerFilename: path.Base(directory), IsDir: 1})
		default:
			http.Error(w, "unexpected method", http.StatusBadRequest)
		}
	}))
	defer server.Close()

	client := New(testConfig("token"), WithEndpoints(server.URL, server.URL, server.URL))
	if err := client.MkdirAll(context.Background(), "/backup/mac/photos"); err != nil {
		t.Fatal(err)
	}
	if err := client.MkdirAll(context.Background(), "/backup/mac/photos"); err != nil {
		t.Fatal(err)
	}
	want := []string{"/apps/bdrclone/backup", "/apps/bdrclone/backup/mac", "/apps/bdrclone/backup/mac/photos"}
	if !reflect.DeepEqual(created, want) {
		t.Fatalf("created = %q, want %q", created, want)
	}
}

func testConfig(token string) *config.Config {
	return &config.Config{
		ClientID: "client", ClientSecret: "secret", AccessToken: token,
		Root: "/apps/bdrclone", UserAgent: "pan.baidu.com", UploadParts: 1,
	}
}